Characterizing the cavities of Anjani Cave in Jonggrangan Karst Area, Purworejo, Central Java, Indonesia

Anjani Cave is located administratively in Tlogoguwo Village, Kaligesing District, Purworejo Regency, Central Java, Indonesia. It is one of the objects of cave tourism. The cave entrance is on a cliff with a triangle-like shape, and the cave roof is 1.9 m in height. The local communities utilize the water flow of the underground river in Anjani Cave for tourist attraction, domestic purposes, and animal husbandry. The research aimed to 1) map the passages of Anjani Cave and 2) to characterize the unmappable passages in the cave. It employed a survey method that included cave mapping and tracer test on the groundwater flow to achieve the first and second objective, respectively. The results showed that the Anjani Cave passage was approximately 400 meters long with an average diameter of 4.1 meters and the total volume of the accessible cave was 6,881 m³. Furthermore, the tracer test identified that the underground river in Anjani Cave was connected to two surface river systems, namely the Cebong Sinking Stream and Jumbleng Sawah Sinking Stream.